XG1v4 box Dolby processing problems

Just "upgraded" to a new XG1v4 4k box and immediately started experiencing the same intermittent center channel audio problems numerous other people have reported on several other threads.

In all cases the info button shows the signal is supposedly DD 5.1+, but on some channels it's clearly only PCM stereo, and in others it changes from literally one minute to the next. Tonight watching Late Night with Seth Meyers the center channel processing was fine whenever the studio mic was on, but when Seth would play a news clip the audio instantly reverted to two-channel stereo.

This didn't happen on my previous legacy Xfinity box, so it's quite clearly a problem in the 4k boxes themselves. 

Extremely disappointed. I guess I have to deal with worse video to get my sound to work correctly again. The XG1v4 box goes back tomorrow.

Ps, I read all of the other threads, and I never did see anyone at Xfinity with an answer, or even indicate they understand the problem. Do you not even employ engineers these days??